• Smart Structures and Systems
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• 제30권2호
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• pp.159-172
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• 2022

To improve the accuracy of the standard penetration test (SPT) results, smart measurement system, which considers the energy transfer ratio into the sampler (ETR_Sampler), is required. The objective of this study is to evaluate the effects of joints and rod length on the transferred energy into the sampler. The energy transfer ratios into the rod head (ETR_Head) and ETR_Sampler, and the energy ratio from the head to the sampler (ER_HS) were obtained using energy modules, which were installed at the rod head and above the SPT sampler. Linear regression analyses are conducted to correlate the ER_HS with the number of joints, rod length, and SPT N-values. In addition, the dynamic resistances are calculated using both transferred energies into the rod head and into the sampler, and are compared with the corrected cone tip resistance measured from the cone penetration test (CPT). While the ETR_Head are generally constant, but the ETR_Sampler and ER_HS gradually decrease along the depth or the number of joints, except at certain depths with high SPT N-values. Thus, the ER_HS can be estimated using the number of joints, rod length, and SPT N-values. The dynamic resistance evaluated by E_Sampler produces a better correlation with the corrected cone tip resistance than that by E_Head. This study suggests that transferred energy into the SPT sampler may be effectively used for more accurate subsurface characterization.

• Progress in Superconductivity
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• 제2권1호
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• pp.11-14
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• 2000

The notion of the finite pairing interaction energy range Td is shown to result in a linear temperature dependence of the London magnetic penetration depth length, ${\Delta}{\lambda}{/\lambda}(0)=(T/Td)2/\pi)ln2$ at low T in the case of the s-wave pairing state, accounting for data of high Tc superconductor by Hardy et al.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2012년도 춘계학술발표대회 논문집
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• pp.511-515
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• 2012

At the moment, with an interest in renewable energy sources (RES) that continue to grow its penetration will be expected to considerably increase in the future power system. However, this penetration of RES leads to new challenges to be solved in electric power systems. In this paper, optimal configuration of renewable energy resources and operation strategy is presented. By using this methodology for allocation of the optimal sizes and types, system operational efficiency and stability of the microgrid will be maximized.

• Elastomers and Composites
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• 제32권3호
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• pp.166-172
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• 1997

The objective in this study was investigated temperature susceptibility and low temperature fracture of rubber modified asphalt. A chlorinated polyethylene elastomer, Tyrin CM0730, was added to 200/300 grade asphalt with 3.0 and 5.0wt% to improve campatibility. The elastomer modified asphalts were analyzed for temperature susceptibility relating to penetration index(PI) and penetration-viscosity number(PVN) as well as low temperature fracture relating to fracture energy $(G_{IC})$. These indices were obtained from the measurements of penetration, viscosity, failure load and modulus. The addition of small amounts of elastomer to the asphalt resulted in a significant increase of both the PI and PVN over an unmodified asphalt. Also, the fracture energy increased with the addition of elastomer to asphalt. These significant improvement at both the high and low temperature result in enhanced performance.

• 한국방재학회 논문집
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• 제9권2호
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• pp.45-51
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• 2009

지구기후모델을 이용하여 예측된 (1) 물성치와 (2) 현재 및 미래의 표면 에너지 입력상수의 가변성을 고려한 동결 및 융해깊이를 예측하기 위하여 확률론적 접근법이 도입되었다. 확률론적 접근법을 예시하기 위하여 극지방에서의 융해깊이 예측을 고려해보았다. 특히 확률론적 융해깊이 예측을 위하여 몬테카를로 시뮬레이션과 함께 Stefan 공식이 사용되었다. 시뮬레이션 결과는 물성치의 가변성을 보여주었다. 표면 에너지 입력상수와 온도 데이터는 융해깊이를 예측하는데 상당한 불확실성을 야기시킬 수 있다.

• 대한조선학회논문집
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• 제49권6호
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• pp.469-477
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• 2012

This paper describes the characteristic analysis of ice impact force for the Arctic structure shape. In the present study an energy method has been used to predict the impact force during the ice-structure collision. This study also employs two concepts for reference contact area and normalized stress in analysis procedure. The influences of factors, such as impact velocity, full penetration depth, structure shape and ice floe size, are investigated. Full penetration occurs, particularly at lower impact velocity when ice thickness increase. But "typical size" ice floe does not expected ever to achieve full penetration during the impact procedure. The structure shape is the dominant factor in ice impact force characteristic. The results for various ice-structure collision scenarios are analyzed.

• Journal of Welding and Joining
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• 제35권3호
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• pp.62-67
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• 2017

The automotive industry is in constant pursuit of alternative materials and processes to address the ever changing needs of their customers and the environment. Applications of laser welding have increased steadily in recent years due to its benefits including high speed, high productivity, and high energy density of heat source. This paper investigated the relationship between laser welding parameters and penetration characteristics. The Welding power was fixed at 5kW and welding speeds were varied for the thickness of the workpiece material. Full penetration occurred in the energy per unit area of $21J/mm^2$. The hardness of the weld zone was different for each strength of the workpiece material, however the lowest hardness values were the same in the heat-affected zone.

• Geomechanics and Engineering
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• 제30권4호
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• pp.337-343
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• 2022

The electrical resistivity method is a well-known geophysical method for observing underground conditions, (such as anomalies) and the properties of soil and rock (such as porosity, saturation, and pore fluid characteristics). The shape of electrodes used in an electrical resistivity survey depends on the purpose of the survey and installation conditions. Most electrodes for field applications are cylindrical for sufficient contact with the ground, while some are conically sharpened at their tips for convenient penetration. Previous study only derived theoretical equations for rod-shaped electrodes with spherical tips. In this study, the theoretical resistance for two cylindrical electrodes with conical tips is derived and verified experimentally. The influence of the penetration depth and tip on the measurement is also discussed.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2005년도 추계학술발표회
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• pp.173-174
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• 2005

• 한국항공우주학회지
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• 제43권5호
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• pp.440-448
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• 2015

운동에너지 막대 탄두 시스템은 기존 시스템의 장점을 결합한 새로운 형태의 요격탄두 시스템으로서 직격 파괴방식에 비해 표적 유도 정밀도에 대한 의존도가 낮을뿐더러, 고폭 파편 탄두 방식보다 더 높은 관통력을 제공해 준다는 장점이 있다. 본 논문에서는 다양한 운동에너지 탄두의 사출 방식 중 등방성운동에너지 탄두의 기폭, 전개모델을 소개하고, TATE 관통방정식을 이용하여 사출된 관통자의 관통 효과를 계산하였다. 또한 교전 성능 분석을 위한 방법을 제시하였으며, 다양한 교전 상황에 대한 몬테-칼로 시뮬레이션을 통해 최적의 교전 기하 및 기폭 시점을 도출하였다.